What are the main cause of rapid population?

I think basic problem of rapid population is illiteracy,people are not aware of such thing,just because lac of knowledge,secondly our government is not giving awareness to low class or you can say in lower tribes,thirdly In our country ,different cast different rule which is made by them selves,which is not amended in our law and route of this cause is dirty politician, literary politician,majority of the politician is not even 12th pass and those people are ruled over the country,then how can you you expect